With new details emerging regarding the NFL's $765 million concussion settlement, many players are reportedly growing concerned that there won't be enough money to go around, according to an ESPN.com report by Steve Fainaru and Mark Fainaru-Wada.

In addition to mass confusion over who will qualify to receive some of the settlement, players are worried about how the NFL will allot the money it agreed to pay out, per sources via Fainaru and Fainaru-Wada:

Based on information from the NFL Players Association and researchers at Boston University, there already are more than 300 cases of former players who would qualify in the highest compensation categories. Payments for those cases alone raise questions about whether $675 million allocated to severely impaired players will be enough.

Pittsburgh attorney Jason Luckasevic, who filed the first concussion-related lawsuit against the NFL in 2011, believes that the players have legitimate reason to be concerned: "It is a very valid concern. It would appear as though there are not enough funds for those that are injured."

According to sources familiar with the league's settlement via Fainaru and Fainaru-Wada's report, one of the other challenges former players are facing is that the proposed settlement would disqualify most players who died before 2006 from receiving compensation, regardless of whether they were diagnosed with brain damage stemming from football-related activity.

There is also confusion as to how the legal teams involved will be paid. According to the report, there's concern that some of the settlement money could be used to pay for legal fees, resulting in "multiple paydays" for some lawyers.

Jeff Hanisch-USA TODAY Sports

On Aug. 29, the NFL announced that it had reached a settlement with the 4,500 former players who filed a lawsuit against the league. The former players claimed that the NFL enshrouded the link between playing football and brain damage.

However, the proposed settlement extends beyond those players who filed the class-action lawsuit and applies to all 18,000 of the league's former players.